1. Field of the Invention
The present invention relates generally to underground lawn and garden sprinkling systems, and more particularly, to a shutoff valve for use with the sprinkler heads installed in such systems for preventing excessive water loss as a result of broken or missing sprinkler heads.
2. Description of the Prior Art
Underground lawn and garden sprinkling systems have long been in common use for periodically supplying water to lawns, gardens, shrubbery and other vegetation. Such underground lawn sprinkling systems include a number of sprinkler heads, sprayers or bubblers adapted to apply water in a desired spray pattern to a lawn, garden, or shrubbery. Sprinkler heads used to water lawn areas are typically mounted flush with ground level to avoid interference with lawn mowers and other lawn working equipment. Typically, the sprinkler heads are coupled by vertically-extending plastic riser tubes to a plastic tee or elbow connector. The lower ends of such plastic riser tubes typically include a male externally threaded fitting for threadedly engaging a female internally threaded port of the tee or elbow connector. The aforementioned tee and elbow connectors are, in turn, connected to a buried water delivery pipe, often made of polyvinyl chloride. Water from a central water supply, such as a municipal water system, is typically coupled to a system of control valves which are manually or automatically opened to selectively gate water to one or more of such water delivery pipes.
The aforementioned sprinkler heads, sprayers and bubbler heads are often made of plastic, and are easily broken when impacted by the cutting blade of a lawnmower or other lawn working equipment. Occasionally, even the pressure of water supplied to the sprinkler heads will, over time, cause the sprinkler heads to unthread from the upper end of the riser and be disconnected therefrom. Even if the sprinkler head is itself made of metal or is otherwise quite sturdy, the plastic riser tubes used to interconnect such sprinkler heads to the buried water delivery pipes are themselves somewhat fragile, and a strong impact to the sprinkler head can often shatter and break the plastic riser tube along its length.
When either the sprinkler heads or the plastic riser tubes are damaged, or the sprinkler heads otherwise become disconnected from the sprinkling system, as described above, a fountain of water, or geyser, is usually seen squirting high into the air out of the ground from the upper end of the riser tube. In addition, because the water pressure in the remaining portion of the underground water delivery pipe is thereby lessened, the remaining sprinkler heads interconnected to that circuit no longer provide sufficient water coverage over their intended spray pattern. Moreover, when the circuit containing the damaged sprinkler head is later shutoff, dirt, mud and small pebbles may seep into the broken riser, thereby contaminating the circuit and causing other sprinkler heads to become clogged when the system is again pressurized.
A damaged or missing sprinkler head often goes unnoticed for days or weeks, particularly if the water control valves are interconnected to a timer, as is often the case. Since the timer eliminates the need for an operator to manually open and close the control valves, it is typical for watering cycles to occur when no one is present to detect a damaged or missing sprinkler head. Moreover, in commercial and municipal watering systems, the sprinkler heads may be physically remote from the control valves associated therewith, and even manual operation of the control valves would not guarantee that the operator would notice such a problem. Furthermore, in hot arid climates like the desert southwest, watering is often timed to occur during nighttime hours to minimize water loss by evaporation. Obviously, detection of damaged or missing sprinkler heads is difficult when watering occurs in the dark.
As mentioned above, a damaged or missing sprinkler head results in an excessive amount of water being applied at the site of the damaged or missing sprinkler head, causing flooding at such site, while resulting in insufficient watering at other points that are intended to be watered by the same circuit. The result is that a great deal of water can be wasted, while the insufficiently watered areas of the lawn eventually discolor and die.
Accordingly, it is an object of the present invention to provide a sprinkler head shutoff valve adapted to sense that a sprinkler head, sprayer, or bubbler has been removed or has broken off from an underground sprinkling system and to prevent any further flow of water at the stie of the missing or damaged sprinkler head.
It is another object of the present invention to provide such a shutoff valve which maintains the water pressure within the circuit that is the interconnected with the damaged or missing sprinkler head for allowing other sprinkler heads supplied with water by the same circuit to function normally.
It is still another object of the present invention to provide such a shutoff valve which prevents the contamination of the underground water delivery pipe with dirt, pebbles or other debris at the site of the broken or missing sprinkler head, and thereby prevents other sprinkler heads from becoming clogged with such debris.
It is a further object of the present invention to provide such a shutoff valve which is of simple and inexpensive construction and which may be easily and quickly installed within new or existing underground sprinkling systems.
These and other objects of the present invention will become more apparent to those skilled in the art as the description thereof proceeds.